Amino-acid amide derivatives have been disclosed as intermediates for medicines in Japanese Patent Application, First Publication Nos. Sho 56-8352 and Sho 62-89696. However, these documents fail to disclose the utility of the amino-acid amide derivatives. Although Japanese Patent Application First Publication Nos. Hei 3-5451, Hei 3-153657, Hei 4-230652, Hei 4-230653, Hei 4-283554, Hei 4-308507, and Hei 4-338372 disclose that some amino-acid amides are useful for biocides, the compounds disclosed in these documents are different from the amino-acid amide derivatives according to the present invention.